The patent application WO-A-99 04661 deals with the risks that may be incurred in these circumstances and, to this purpose, discloses a protection arrangement that is intended to be fastened on to the back of the user by means of braces, straps, belts or the like, in which such an arrangement comprises two supports which are aligned vertically with and joined to each other by means of a hinging button extending perpendicularly to the spine. Both supports are constituted on the outer side by a plurality of substantially rigid plates featuring a honeycomb structure, and on the inner side (i.e. in contact with the user's back) by a continuous layer of foam material, as well as by a continuous intermediate layer of soft material capable of absorbing that share or portion of impact-induced energy that fails to be absorbed by a permanent deformation of the honeycomb structure. In each one of said two supports, the plates are connected to each other by means of book-like hinges, whose axis extends in a direction that is perpendicular to the longitudinal axis of the protection arrangement, this axis being practically coincident with the spine of the user, so as to be able to compliantly follow the curvature of the same spine without any discontinuity being created between a plate and the next one.
This prior-art protection arrangement, however, is not effective in solving the totality of the above-mentioned problems, since:
a) the honeycomb structure of the plates is effective in taking up through its own deformation solely those blows that are directed perpendicularly to the plates themselves;
b) owing to the permanent deformation of the plates, the protection arrangement becomes unserviceable upon receiving just a single bump or impact;
c) its effectiveness is anyway restricted owing to both the fact that the rotation about the axis of the hinges is the sole degree of freedom of the plates with respect to each other in each one of the two supports is, and the fact that, along the however narrow strips formed by the same hinges, there is no honeycomb reinforcement available;
d) in the case of a bump imparted or suffered exactly in correspondence of the hinging button between the two supports, which practically comes to lie at the level of the lumbar vertebrae, the possibility exists for the same button, which has a definitely small cross-section area, to exert on to the back of the user a localized pressure (compression) that may be quite high.
U.S. Pat. No. 5,140,995 discloses a protective device consisting of many identical plates, made of deformable plastic material, which are positioned one behind the other in a longitudinal direction of the spinal column, in a limited overlapping relationship. There is no possibility for each of the plates to freely rotate with respect to the others in consideration that they are individually connected to an underlying flexible shield by means of rivets at the four corners thereof. As a consequence the protection afforded by the device is restricted to a rather limited range of directions of the impact bump. Moreover, the plates have a width which is substantially limited to the vertebrae and do not ensure a protection to other parts of the skeleton, such as the ribs of the chest.
Also FR 2,676,178 discloses a protection device consisting of various arched plates, made of deformable plastic material, which are positioned one behind the other, with a certain overlapping, above a common flexible sheet to which they are fixedly connected in correspondence of zones at the sides of the spinal column. In this case the plates are sufficiently wide to protect also the ribs but the distribution of the impact force to the adjacent plates is permitted by flexible rods which does not ensure a firm, though localized, interconnection of the plates.
GB 2,328,859 discloses several devices which comprise a flexible sleeve to be worn about against the various parts of the body to be protected, including the chest. The devices make use of rigid plates which are interconnected in overlapping relationship and attached to the sleeve in such a way to have only a limited relative movement.
DE 195 27 036 discloses a protection device for the spinal column consisting of various plates which are positioned one behind the other in a partially overlapping relationship and are interconnected by at least one longitudinally aligned connection element having the purpose of preventive a mutual sliding of the plates. The protection afforded by this device is quite low in case of severe impacts in consideration of the flatness of the plates and relies entirely on the shock-absorbing nature of the material (preferably plastic foam) with which the plates are made.
Also the device disclosed by DE 196 01 151 does only rely its protecting action on the shock-absorbing nature of the material (preferably plastic foam) with which its plates are made.
The protective device disclosed by U.S. Pat. No. 5,402,742 is only restricted to the lumbar area of the spinal column and makes use, among other, of T-shaped elements of plastic interlocking with one another and fastened to a back part by rivets inserted at the four corners of the transversal arm. The elements have only a limited flexibility.
At last, the protective device disclosed by U.S. Pat. No. 5,328,447 comprises a plurality of upper support members having a convexity in correspondence of the spinal column. Each of said upper members fits over a pair of lower members in mating relationship and makes use of fastening means which only permit a mutual rotation along the longitudinal direction of the spinal column.